Dutch Elm Disease Surveillance & Management

Dutch elm disease (DED) is a fatal fungal disease spread by elm bark beetles. Thefungus blocks the tree’s water-conducting tissue, causing wilting, yellow “flagging”branches and death, often within a single season.

Surveillance is the systematic search for infected elms and illegal elm firewood sothey can be removed before beetles carry the disease to healthy trees. The sooneran infected tree is found and destroyed, the fewer neighbouring elms are lost.

What DED surveillance involves:

• Summer ground surveys – Symptoms usually show from mid-June, so trained arborists survey streets, back lanes, parks and private yards from June through August.
• Marking and tagging – Infected trees and elm wood are marked with orange paint and a numbered metal tag.
• Lab confirmation – Branch samples can be tested in our in-house Plant Disease Diagnostic Laboratory.
• GIS mapping – Every tree is recorded with GPS location, size and condition, soremovals can be planned and tracked.
• Prompt removal and disposal – Marked material must be destroyed within the mandated window, typically two weeks, by chipping or delivery to an approved elm disposal site.

1. Survey – Arborists inspect your elm population and record every suspect tree in ArcGIS.
2. Confirm – Samples are tested in our diagnostic lab when symptoms are unclear.
3. Notify – Our Customer Service Coordinator contacts property owners and handles access and authorization forms.
4. Remove – Crews fell infected trees, cut stumps flush or debark to the soil line, and use cut-and-carry where equipment can’t reach.
5. Dispose – All elm material is chipped to 5 cm or less or hauled to the designated disposal site.
6. Report – You receive a completed data sheet and map of every tree removed.